This application claims priority of Japanese Patent Application No. 2001-247254, filed on Aug. 16, 2001.
1. Field of the Invention
The present invention relates to a vehicle theft prevention device. More particularly, the present invention relates to a vehicle theft prevention device mounted on a vehicle such as an automobile to prevent theft of the vehicle when it is stopped.
2. Description of the Related Art
Conventionally, since a moving body such as an automobile capable of moving by itself can be easily conveyed to a remote place by a thief, it is difficult for an owner of the automobile to find the stolen automobile. Especially, a four-wheel drive car or deluxe car is conveyed abroad, in some cases, after it is stolen. Accordingly, it is important to get back a stolen automobile before it is conveyed to a remote place by notifying the police of the theft at the time of occurrence of the theft.
According to the recent development of technology for moving body communication, the size of an automobile telephone has been reduced and further the price has been decreased. Therefore, it is easy to incorporate the telephone into an automobile. Accordingly, various vehicle theft prevention devices have been recently proposed, in which the automobile telephone is combined with a navigation device utilizing GPS (Global Positioning System), and after a vehicle has been stolen, a position of the stolen vehicle is detected by the navigation device and the thus detected vehicle position is transmitted to a base station by the automobile telephone.
For example, Japanese Unexamined Patent Publication No. 10-132917 discloses a vehicle position detecting system, the constitution of which is described as follows. An automobile telephone is connected with a vehicle position detecting system composing a navigation system. When an owner of the vehicle finds out that the vehicle has been stolen, the owner calls this automobile telephone from a nearby telephone. Then, the navigation device detects a present position of the vehicle by a signal of the automobile telephone which has been called from the outside, and the thus detected present position of the vehicle is transmitted to the owner via the automobile telephone. Therefore, the owner of the vehicle can confirm the present position of the stolen vehicle.
However, the aforementioned vehicle position detecting system has the following disadvantages. It is impossible for the owner to confirm the present position of the vehicle until the owner recognizes that his vehicle has been stolen. Accordingly, there is a risk that the stolen vehicle is conveyed abroad in the meantime where it is impossible for the electric waves of the automobile telephone system to reach the automobile. Further, there is a possibility that the receiver or antenna of the stolen vehicle is removed or broken by a thief after the vehicle has been stolen. Therefore, it is impossible for the navigation device, which is provided in the vehicle, to detect its position even if the owner of the vehicle calls the automobile telephone of the vehicle. In the case where the navigation device is out of order, it is impossible to detect the present position of the vehicle. Therefore, it is impossible for the owner of the vehicle to confirm the present position of the vehicle.
It is a first object of the present invention to provide a theft prevention device characterized in that a base station can immediately recognize that a vehicle has been stolen when the occurrence of theft and the present position of the vehicle are transmitted to the base station immediately after the theft of the vehicle has been detected. It is a second object of the present invention to provide a theft prevention device characterized in that even when a navigation device of a vehicle is out of order, the theft prevention device can immediately detect the failure of the navigation device and the can determine position where the navigation device became out of order.
The characteristics of the present invention to accomplish the above objects are shown in the first to the eleventh aspect described below.
In the first aspect, there is provided a theft prevention device comprising: a position detecting means for detecting a position of a moving body on the earth; a theft detecting means for detecting theft of the vehicle; and a transmitting means, wherein after the theft detecting means detects theft of the vehicle, a position of the vehicle is detected by the position detecting means and transmitted to a predetermined position by the transmitting means, the theft prevention device further comprising a position storing means for periodically storing a position of the vehicle detected by the position detecting means, wherein when the theft detecting means detects theft of the vehicle, the transmitting means transmits the latest positional information stored in the position storing means.
In the second aspect, there is provided a theft prevention device according to the first aspect, further comprising an abnormal state detecting means for detecting an abnormal state of the position detecting means, wherein when the abnormal state detecting means detects an abnormal state of the position detecting means, the transmitting means transmits the latest positional information stored in the position storing means.
In the third aspect, there is provided a theft prevention device comprising: a position detecting means for detecting a position of a moving body on the earth; a theft detecting means for detecting theft of the vehicle; and a transmitting means, wherein, after the theft detecting means detects theft of the vehicle, a position of the vehicle is detected by the position detecting means and transmitted to a predetermined position by the transmitting means, the theft prevention device further comprising: a position storing means for periodically storing the position of the vehicle detected by the position detecting means; and an abnormal state detecting means for detecting an abnormal state of the position detecting means, wherein when the abnormal state detecting means detects an abnormal state of the position detecting means, the transmitting means transmits the latest positional information stored in the position storing means.
In the fourth aspect, there is provided a theft prevention device according to one of the first to the third aspects, wherein at least the position storing means is accommodated in a casing which is separate from a casing in which the position detecting means is accommodated.
In the fifth aspect, there is provided a theft prevention device according to one of the first to the fourth aspects, wherein the position detecting means turns on an electric power source of a circuit necessary for periodically detecting a position of a vehicle and detects the position of the vehicle even in an alert state of the vehicle after the vehicle has stopped or in a state in which the position detecting means does not operate.
In the sixth aspect, there is provided a theft prevention device according to the fifth aspect, wherein the transmitting means periodically transmits the latest positional information stored in the position storing means even after the completion of the first transmission.
In the seventh aspect, there is provided a theft prevention device according to one of the first to the fifth aspect, the position detecting means including: a first position detecting means in which GPS is utilized; and a second position detecting means for detecting a position of the vehicle by using a movement parameter of the vehicle and also using an azimuth parameter based on terrestrial magnetism wherein, when the first positional detecting means is out of order, the second positional detecting means detects a position of the vehicle on the basis of the latest positional information stored in the positional storing means, and the transmitting means periodically transmits the position of the vehicle.
In the eighth aspect, there is provided a theft prevention device, according to the sixth or the seventh aspect, wherein a periodical transmitting period of transmitting a position of the vehicle by the transmitting means is different from a position detecting period of detecting the position of the vehicle by the position detecting means.
In the ninth aspect, there is provided a theft prevention device according to one of the first to the eighth aspect, wherein the transmitting means transmits a signal to a monitoring center which monitors the vehicle theft and the abnormal state of the position detecting means at all times when the vehicle theft or the abnormal state of the position detecting device is detected.
In the tenth aspect, there is provided a theft prevention device according to the fifth aspect, wherein the theft detection means judges that the vehicle has been stolen when a position of the vehicle is greatly different from the previously detected position of the vehicle in the case of periodically detecting a position of the vehicle by the position detecting means.
In the eleventh aspect, there is provided a theft prevention device according to fifth aspect, wherein the theft detection means judges that the vehicle has been stolen when the position detecting means does not operate in the case of periodically detecting a position of the vehicle by the position detecting means.
According to the present invention, when it is detected that a vehicle has been stolen, the occurrence of vehicle theft and the present position of the stolen vehicle are immediately transmitted to a predetermined base station. Therefore, the base station can immediately grasp the occurrence of vehicle theft. Even in the case where a navigation device of the vehicle is out of order, the base station can immediately grasp the abnormal state and a position where the abnormal state occurred in the vehicle.